The battle of the bulge

Deciphering satiety signals from the gut to the brain, could help devise smart food designed to communicate feeling of fullness to the brain, and thus help fight obesity

We know nutrients interact with gut cells, which dispatch chemical messengers – hormones– to the brain to signal “stomach full.” This messaging from our food to gut to brain is now being decoded to fight obesity.

Until now, gastric bypass surgery has been the fastest way to treat obesity. Not only does it cause weight loss, but it can also cure diabetes in some. “The resolution is almost instantaneous indicating that mechanisms other than weight loss itself are responsible. This has turned the focus towards appetite-regulating hormones from the gut,” endocrinologist Jens Holst of the University of Copenhagen, Denmark tells youris.com.

What if you could cause the same effects, without surgery? Holst discovered a small molecule in the gut, called glucagon-like peptide-1 (GLP-1), which acts on parts of the brain that regulate appetite. He is now involved with a EU funded research project, Full4Health, which aims to reveal how food can trigger signalling mechanisms communicating feelings of hunger or fullness to the brain.

“There is a raft of hormones, which are all satiety hormones, which will tend to help terminate a meal,” says project coordinator Julian Mercer, obesity scientist at the University of Aberdeen, UK. “We don’t know much about which nutrients are involved and whether we can manipulate how food interacts with those signalling systems and how those systems are integrated at different levels in the brain.”

The project could help pinpoint future drugs for either obese people or those who have trouble consuming enough nutrients. “It would be even better if we could come up with smart food,” says Mercer. Insights will feed into another project which seeks to develop ingredients capable to giving the feeling of fullness called SATIN.

The research stands out from similar previous studies by focusing on males and females, lean and overweight people, from four age groups including children, teenagers, adults and elderly. “If we are looking to reformulate foods to come with additional benefits built into them, those reformulations will likely vary in different groups,” says Mercer. So no one size will fit all.

Steve Bloom, gut protein expert at Imperial College London, UK, says the project addresses a large problem with substantial research funds, but the aspirations are vague. “It’s a worthy endeavour but I doubt any breakthrough will occur. I’d be delighted to be wrong,” he tells youris.com.

Its chance of success may be limited because studying internal satiety factors would not impact external factors affecting the way people eat. “It is very challenging and that is because feeling satiated does not necessarily stop people from eating,” comments Ellen van Kleef, behavioural expert at Wageningen University in the Netherlands. “Manipulating information about the nature of the food provided, [such as] caloric or fat content, or situational context, [by] framing a food as a meal versus a snack, influences perception, choice, satiety and the amount of food people eat,” van Kleef explains. “This interplay between internal signals of hunger and satiety and external signals makes it very challenging,” she adds.